Problem 4 · 2014 Math Kangaroo
Easy
Ratios, Rates & Proportions
unit-ratedistance-speed-time
Whenever Koko the koala bear is awake, he always eats 50 grams of leaves in one hour. Yesterday Koko slept for 20 hours. How many grams of leaves did he eat yesterday?
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Answer: D — 200 grams
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Hint 1 of 3
Koko only eats when he is awake, so first work out how many hours he was awake.
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Hint 2 of 3
A whole day is 24 hours; take away the hours he slept.
Still stuck? Show hint 3 →
Hint 3 of 3
For each awake hour add another 50 grams of leaves.
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Approach: find the awake hours, then add 50 grams for each one
- A day is 24 hours and Koko slept 20 of them, so he was awake 24 − 20 = 4 hours.
- Each awake hour he eats 50 grams, so count by fifties for the 4 hours: 50, 100, 150, 200.
- That is 200 grams in all.
- Answer: 200 grams.
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